1. Field of the Invention
One or more embodiments of the present invention relate to a shadow area compensating system, medium, and method, and more particularly, to shadow area compensating system, medium, and method which that may significantly increase the luminance of each pixel in a dark area with respect to pixels positioned in the vicinity of the corresponding pixel and slightly increase the luminance of each pixel in a bright area.
2. Description of the Related Art
Generally, an image input by an image input device includes a variety of information, including luminance and chrominance information, for example. However, when components of the corresponding luminance signal are uneven or distorted, it is difficult to clearly visually represent an object included in the image. In particular, when the luminance distribution is uneven, it may be difficult for a viewer to distinguish between objects in dark areas of such an image.
In order to overcome such problems, techniques for improving the luminance have been proposed. For example, in U.S. Pat. Nos. 5,132,796 and 5,255,093, the visibility of a shadow area is improved by adjusting the luminance for the entire output image based on an overall luminance of the input image.
In U.S. Pat. No. 5,394,195, the visibility of a shadow area is improved by again compensating the luminance of the entire output image using information on a portion of an input image. Similarly, U.S. Pat. No. 6,414,659 sets forth a technique for improving the visibility of a shadow area by compensating the luminance of an output image according to luminance characteristics of the corresponding display device, regardless of the input signal.
In the above-mentioned techniques for improving luminance characteristics of an output image by compensating the luminance of the input image, the luminances of pixels having the same intensity are respectively improved to the same extent regardless of the brightness levels of differing respective areas in which the pixels are positioned. In addition, the luminances of pixels are improved regardless or whether they correspond to a dark area of a bright area. In addition, systems that compensate the luminance consider only the characteristics of a display device, regardless of the input image, and cannot properly compensate the luminance of a low-luminance image.
In addition to the above, Korean Publication Patent No. 2005-0042699 discusses a technique where a luminance compensating section is determined by dividing an input image into a plurality of macro blocks and micro blocks and a representative luminance of each block is then calculated. Thereafter, the luminances in the determined compensating sections are increased the same extent throughout the respective sections. Even in this technique, the luminances of pixels in a partial area are increased, resulting in the whole luminance not being improved. However, since the same luminance compensation is performed for a plurality of pixels having the same luminance, the luminance of each pixel does not reflect the luminances of pixels positioned in the vicinity of the corresponding pixel.
In addition, in such techniques for overcoming the above-mentioned problems, it is also difficult to implement the same in memory in real time.